Tape feed suppressor



June 7, 1949. v GOETZ 2,472,701

TAPE FEED SUPPRESSOR F1166. Sept. 20, 1945 INVENTOR- muaus. 1'. 0512 avg 7 Z ATTOF lNEY jt en r iz select ng m mber .o a lega periora which e for t sta thi dtape i h an .unin ll ibl Patented June 7, 1949 STATES ATENT OF CE TAPE FEED SUPPRESSOR -M aurus T. Goetz, Chicago, Ill., assignor to Teletype Corporation, Chicago, 111., a corporation re -De awa e App i ation Se t mbe 2 1945, Se ia N9- 7,5

h nvent o r la e t leg a h syst and apparatus and more 'particularlyi'to tape'conr trolled-transmitting devices and apparatus for suppressing the tap feedi goperation of such ,devices.

Signaling systems are desirable wherein it is required that messages be rendered unintelligible to personsunauthorized to receive them. Sur- .re ptitious interception ,of messages may be accomplished for example, inithe case of "wirecomr munications by tappinglslgnalwiresj and intrad io .communicationby means of receiving apparatuses tuned to vth proper frequencies.

A /signaling system, disclosed in :.U. S. ,Patent 1510., ;1-,31Q,7 1-9',-.issued to Gilbert S. Yernam, shows a method of, enciphering the' .message.to betrans- .xnitted, {which consists injtransmittinglover the line for each character oft th lmssage ,a .set of impulseswhich represents the combination .of the true vmessage impulseswith a secondjset of impulses arbitrarily .chosenandchangin .for each character transmitted.

Such a resulthas been obtained by perforating the't uelmessa e qnah kecor t peme forat n a simila tap .wi hla an 2marran eme v cha ea ers, r ning the tw tapesgin synchronis throu twotape transm ter hiQh jo n c.0

101.vlih utlifl l li ififiopn im ulse oh lin o i n o th e e ma neti un quence of characters representingacornbination ft m sa e an and mak r pos -ta This uni e i ble r.e pher d me sa h r ra mitted over. thelineand may be recorded byany suitable receiving device.

: l r ecipher h suc m s ag it i vea eni e that the receiving ,station be provided with a duplicate of the;transmittingstationfs key code tape. ;T he key cbde'tape is.; fe'd througha tape transmitter at such aspeed that the character impulses of thegkey code 'tlape' a're combined synchronously with: the "character impulses of' the message to exert a joint control' on the'selecting mechanism of a; local printer, resulting" in the printingpf the original mesagetin deciphered {form Fo-r;exan iple, if the first characterof the key code to be gombined with the first character ;of' thetrue message is the letter 'A, the first a a t of ill -k lcqde at th vIt?a r n St el! to be combined with the enolphered' ,rnessage would also have to be th e letter ,Ailin orderto decipher the first character "offthefm essage.

In a system of this character wherefradio trans- .rm ss e i F sed; siaii i z i ii rp te E ste mitting 'statiqn combined with the share pulses of thetrue message, thusmaking it 'sible tordecipher the message.

Therefore, the primary iec vo h s inrei i isv o provid manua mea s r ens-press n the eed operation .of. the ike code .Wlfiilfflfilfli til the cha a te impu s s .o he. .key; code tape and the character impulses of the enciphered message are in synchronism so that the incoming message may bedeciphered. Another object of this invention .is ;toprovide a nonrepeat leverso that the operator .can',ohly suppress one-tape feeding operation for each manipulation of. the tape feedi suppressing means, thus precluding the operator "from inadvertently retarding the lgeyfcode tape more than necessary to bring vit back into synchronism with the jen- .ciphered message.

Although it has been set forth hQW, thetape .ieed suppressor embodyingthe present invention ,can be used as a synchronizing means in asecret signaling System, it isto be understood that'itsuse is not limited to such extent. For example, the present invention .couldjbe 'usedias a means for repeating signal impulses recorded inja record tape. 4 v t 4 'The apparatus embodying the present invention in general consists of a manually operatedtripoff lever which, when operatedunlatches a .pivoted member, allowing itto rotat'ein a counterclockwise direction under the urging of its associated spring until a pawl secured. thereto isiin latching engagement with the tape feedleverin its lowermost position, thus precluding said tape feed lever from rising'to- -engage the next tooth with the tape feed leverj A rignrepeat'jlever is M de eae tain t ssli'seia teaser?- pression operation is performed for each operation of the trip-off lever.

A more complete understanding of the foregoing and other objects and features of the present invention may be had from the following description when taken in conjunction with the accompanying drawing, wherein like reference characters designate similar parts throughout the several views, and in which,

Fig. i is a front sectional view of a tape transmitter with the apparatus embodying the present invention attached thereto, and

Fig. 2 is a perspective view of the apparatus embodying the present invention with only those parts of the tape transmitter necessary to show the operation of the tape feed suppressor shown.

Having reference to Fig. 1, the structure embodying the present invention comprises a base casting I I of a telegraph apparatus such as a tape transmitter, which supports a pair of side frames I2, only one of which is shown, which frames afford end support to a pivot shaft I3, upon which is mounted pivotally a set of five feeler levers I4. A sensing pin I5 is carried upon the uppermost extremity of each one of the feeler levers I4 and is of sufiicient length so as to extend through the perforations in the record tape It When its associated feeler lever I4 is in its extreme counterclockwise position. An individual contact carrying block I! secured at I8, each upon an associated one of the feeler levers I4, carries between the insulation plates I9 a contactor strip 2| upon Whose extremity there is provided a double sure faced contact point that may engage with one or the other of a pair of opposed contact screws 22 A spring 24 individual to each contactor and feeler lever assembly is preferably soldered to its associated contactor 2| and is secured to an individual contact plate 25 mounted, along with other and similar contact plates 25, upon an insulation terminal block 25 which is secured to side frames I2. To these plates 25 there may be secured the impulse channel wires which communicate with a signal distributor apparatus, such as a rotary I segmented distributor 21 commonly used in telegraph systems.

The distributor 21 consists of a segmented distributor ring 28 which consists of seven segments, five of which are character signal segments which are connected by means of conductors to plates 25, each individual to its associated feeler lever I4, and the remaining two segments are the conventional stop and start segments and are arranged similar to the standard five unit Baudot code start-stop sequence. A distributor shaft 29 carries a brush arm 3| which supports a pair of brushes 32 that connect the segmented ring aforementioned with a solid ring (not shown) inside and concentric therewith. The inner solid ring is connected to a transmission line so that when any potential is applied upon any of the segments, it is conducted over the brushes 32, through the inner ring, and over the outgoing line.

Power is derived from a motor 33 which drives a pinion 34 cooperating with a gear 35, and through a friction clutch 35 drives the shaft 29. The shaft 29 is restrained in a start-stop manner by a stop cam 31 (Fig. 2) and a stop arm 39 controlled by an electromagnet (not shown), the arm 38 operating to release shaft 29 when the magnet is energized.

Secured to the lower extremity of shaft 29 is a cam 39 (Figs. 1 and 2) which controls the oscillation of a rocker arm 4| pivoted at 42. Located at the leftward extremity of rocker arm 4 I, as seen in Fig. 2 is an adjustment screw 43 which cooperates with an extension finger 44 of an operating bail 45 which is mounted pivotally between side frames I2 (Fig. 1). Thus, it may be seen that for each revolution of shaft 29, due to the rocker arm 4| cooperating with the cam 39, Figs. 1 and 2, the operating bail 45 is rotated in a clockwise direction to its extreme clockwise position and returned to its normal position as seen in Fig. l.

The individual springs 24 exert a counterclockwise force upon the contact levers I4 tending to maintain the levers I4 in contactual engagement with bail 45. When the operating bail is in its counterclockwise position, as shown in Fig. 1, all of the levers I4 are so disposed that their c0ntactor tongues 2| engage the uppermost ones of the contact screws 23 and their sensing pins I5 are retracted so as not to engage the perforated tape I5.

On the other hand, when the ball 45 is in its extreme clockwise position, the several feeler levers I4 will respond to the urging of their individual springs 24 and will extend or attempt to extend their sensing pins l5 upwardly through the tape I6. When a transverse row of perforations in the tape is presented opposite the alignment of pins I5, the absence of a perforation prevents its associated lever I4 from rotating beyond that point at which it engages the tape, thereby precluding its contactor 2I from engaging the lowermost contact screw 22. When a perforation is presented opposite any pin I5, the pin is permitted to enter such perforation and the associated lever I4 continues to rotate until its contactor 2| is in engagement with the lowermost contact screw 22. The contact screws 22 and 23 are respectively connected to various sources of current sup-ply such as positive and negative current,

or current and no current, in a manner well known in the art, so that the conventional marking and spacing signals may be transmitted to the distributor 21, as previously described.

The tape I6 is fed leftwardly as viewed in Fig. 1 through the engagement of feed perforations in the tape IS with a sprocket wheel 41 having spaced pin teeth, and carried upon a sprocket feed shaft 48 which is rotated in a, counterclockwise direction in a step-by-step manner when the detented ratchet wheel 49 integrally associated therewith has its teeth successively engaged by a reciprocating pawl 5|.

The feed pawl 5| is secured pivotally to the rightward extremity of arm 52 of the feed lever 53 and is urged in a clockwise direction by a flat spring 54. The feed lever 53 is mounted pivotally on shaft I3 and is urged in a counterclockwise direction by a spring 55 until the arm (Fig. 2) is in abutment with the operating bail 45 in a manner similar to the feeler levers I4. When the operating bail 45 is moved to its clockwise position, the feed lever 53 is permitted to rotate in a counterclockwise direction, thereby raising the feed pawl 5! so it can engage the succeeding tooth of the ratchet wheel 49. As the operating bail 45 is returned to its normal position, Fig. 1, the feed pawl 5I, through the engagement of the feed lever 53 with the operating bail 45, is lowere thereby advancing the ratchet 49 the space of one tooth and feeding the tape the distance necessary to bring the next transverse row of perforations in alignment with the sensing pins I5 to be probed thereby.

A bracket 56, Figs. 1 and 2, is secured to base casting II and pivotally supports member 51 by m'eans -oraistud: 66. s :ThemembefiSl ie urged in a counterclockwise:direction upsetting-a which is secured to an: extension 59--bf the-bracket 56; The member-5'| ,"-through its projection 63 l' i's re: strained in-its=extreme clockwise position by a shoulder 6| of a manual tape feed suppressor trip-off lever 62, secured pivotally to the bracket 56by a stud 68 and urgedin a counterclockwise direction by a spring 64 secured to'a projection of the bracket 56. Also mounted pivotally on stud 66 is a pawl 65 which is biased in a clockwise direction by a spring 66 and normally abuts against astop member 61 secured to' th'e member 51.

A 'reset lever 69 having a slott'd portiorf'fl,

shown in dotted outline in Fig'tIf-is"mouritd'slid ably on pivot stud 6i) and is urged-in a clockwise direction by a spring 13 securedto'bracket '56 and engaging a downwardly extending projection 14 of the reset lever 69. An eccentric adjusting screw '15 is secured to an upwardly extending portion 12 of the lever 69 and abuts against the leading vertical edge of the member 51 to limit the clockwise rotation of the reset lever.

A nonrepeat lever 16 secured pivotally to bracket 56 by the stud 68 is biased in a clockwise direction by a spring 86, secured to the trip-oil lever 62, and has a shouldered portion 11 which normally confronts the shouldered portion 6| of the lever 62. It is observed that shoulders 6| and T! are not in direct horizontal alignment, but that shoulder Si is slightly higher than shoulder 11. The purpose of this arrangement will be more clearly shown in the operational description which will follow hereinafter.

Assume the tape transmitter to be operating under normal conditions with the start magnet (not shown) energized so that the stop arm 36 (Fig. 2) is disengaged from stop cam 31 thereby permitting shaft 29 to rotate. As previously mentioned, rocker arm Al oscillates, thus oscillating the operating bail 45 which intermittently raises the sensing pins i5 of the feeler levers M (Fig. 1) so they may probe the tape I6, and also raises the feed pawl 5| so it may engage the succeeding tooth of the feed ratchet 45 to advance the tape I6.

If for some reason the operator or attendant desires to suppress the tape feeding for one cycle of operation, the operator depresses the trip-off lever 52 (Figs. 1 and 2) thus rotating it in a clockwise direction until the shoulder 6| thereon is no longer blocking the projection 63 of the member 5?, thereby allowing the member 51 to rotate in a counterclockwise direction under the urging of its associated spring 53. As the member 51 is rotated, stop member 61 thereon urges the pawl 65 in a counterclockwise direction until it abuts against the member 18 secured to the rightward extremity of the arm 52 of the feed lever 53. During the immediate cycle of operation, as the operating bail 45 is rotated clockwise, the feed lever 53 is urged in a counterclockwise direction by its associated spring 55 until it is restrained by means of the pawl 65 latching the member 18. It may be seen in Fig. 1 that although the feed lever 53 will rotate to some extent with the pawl 65 latching the member 78, it will not rotate sufiiciently to permit the feed pawl to engage the succeeding tooth of the feed ratchet 49, thereby suppressing the tape feed function, and thus causing the sensing pins I5 to probe the same transverse row of code perforations a second time.

When the member 51 is rotated in a counterclockwise direction, its leftward vertical edge en gages the screw 75 to rotate the reset lever 69 in a c'ounterclockwisedirection-so that the shoulder 19 is in the path of the operating bail' 45. As the' operating ibaikdirotates'in a clockwise direction, it' engages tlie shoulder 19 0f the reset lever-69 which; through the instrumentality of the slot H (Fig.- 1) is'movedri'ghtwardly causing the screw 15 tFigs. l and zlmounted thereon to rotate the member S'I in-"a "clockwise-direction until the pro jec'tioi-i '63 is "latched in its inoperative position" by either the trip-01f lever 62" or the nonrepeat lever 76, whichtogether comprise a double tripoft-latch; I j

fit'istobe noted that the reset lever 69 is oper i ate'd "simultaneously with the counterclockwise rotation of the feed lever 53." Thus, the member 161s provided with a tooth-like portion 8|, a'n'd" the latching' portion of the pawl 65 is substantially hook shaped so that member 18 and pawl 65 cannot disengage until the feed pawl 5| is in its lowermost position even though the member 57 carrying stop member 6? is rotated to its latched position before the operating bail restores the tape feed lever 53 to its normal position.

It is also to be noted that although the operator may depress the trip-off lever 62 for a longer time than is necessary to complete one cycle of operation, the nonrepeat lever 16, biased in a clockwise direction by the spring 86 will latch the projection 63 when the member 57 is restored to its inoperative position as previously described. The member 51 will remain latched by the nonrepeat lever 16 until the operator releases the trip-off lever 62. When the trip-off lever 62 is released the shoulder 6| thereon abuts the shoulder 11 of the lever 16, thereby moving the shoulder 11 out of the path of the projection 63 of the member 51 which is latched by the shoulder 6| of the lever 62.

As previously mentioned, the shoulder 6| of the lever 62 is slightly higher than the shoulder ll of the lever l6 so that when the operator depresses the trip-oil lever 62 to release the member 57. the shoulder ll of the lever 16 will be lower than the upper surface of the projection 63, thereby precluding it from latching the projection 63 until the member 51 is restored to its unoperative position at the end of the cycle of operation.

Although a specific embodiment of the inventicn been disclosed in the drawings and described in the specification, it is to be understood that the invention is not limited to such specific embodiment but may be modified and rearranged without departing from the spirit and scope of the invention.

What is claimed is:

F. In a record reader for telegraphic transmitt ng devices, a record feeding mechanism coma cyclically moving member, means for actuating said member subsequent to each reading of the record, and means comprising a double trip-01f latch cooperable with said cyclically moving member to invariably defer the actuation of said feeding mechanism for a time period of one cycle.

2. In combination, a telegraphic tape transmitter comprisin continuously cyclically operable driving means, means for sensing a telegraphic tape, said driving means actuating said sensing means, a tape advancing mechanism, said driving means also actuating said tape advancing mechanism subsequent to each reading of said tape, and means comprising a double tripoff latch cooperable with said cyclically operable driving means for invariably suppressing the 7 operation of said tape advancing mechanism for a time period of one cycle.

'3. In combination, a telegraphic tape transmitter comprising a continuously cyclically operable member, means for sensing a telegraphic tape, said sensing means actuated by said operable member, a tape advancing means comprising a cyclically moving member and tape advancing instrumentalities, said tape advancing means actuated by said cyclically operable member in timed relation with said sensing means, a manually controlled instrumentality, means initiated by said manually controlled instrumentality to suppress the operation of said tape advancing-means by engaging said cyclically moving member, a member controlled by the third recited means cooperable with said cyclically op- 8 arable member to disengage said third recited means from'said cyclically moving member, and means to latch said third recited means after one cycle of operation of said operable means. MAURUS T. GOETZ.

' REFERENCES CITED The following references are of record in the iile of this patent:

UNITED STATES PATENTS Number Name Date 1,460,357 Kleinschmidt Oct. 29, 1935 1,900,772 Smart Mar. 7, 1933 2,018,812 Schmidt Oct. 29, 1935 2,355,657 Lake Aug. 15, 1944 2,401,454 Bemis June 4, 1946 

